Rice Lake Transducer Simulator 4 - Manual

© Rice Lake Weighing Systems 37300 11/96
230 West Coleman Street • Rice Lake, WI 54868 • USA
TEL: 715-234-9171 • FAX: 715-234-6967
Transducer Simulator 4 Operating Instructions
The Transducer Load Cell Simulator 4 is a valuable and versatile diagnostic tool. Simulator 4 was designed
by people who use simulators day in and day out for their own use. It will give you years of precision service
if you take a few minutes to learn how to use and maintain it.
What is a Load Cell Simulator? - Simulators provide a convenient, repeatable way to generate signals
identical to those that strain gauge load cells and pressure transducers produce when load is applied to
them. These signals can then be used to calibrate or test indicators, amplifiers, or power supplies with a
known stable signal.
What kind of signals will I get out of the Simulator? - Simulators, like the load cells they simulate, are
passive devices. You don't get anything out until you put something in. What you put in is the Excitation
Voltage. The output of the simulator is proportional to the signal applied. If, for example, we "excite" the
simulator with 10.00 VDC with the selector switch set to 1.00 mV/V, the output would be 10 X 0.001 =
0.010V or 10 mV. If we change the excitation to 15.00 VDC, then the output would be 15 X 0.001 = 0.015V
or 15 mV. The simulator always provides a signal which is proportional to the input voltage. Precision simu-
lators, such as the Simulator 4, can be used with a precision power supply to provide a laboratory source of
millivolt reference.
What kind of cells can I simulate? - The Simulator 4 main bridge is set for 350
Ω
cells, the industry
standard. The simulator can also be used to test instrumentation connected to 240
Ω
, 400
Ω
, 700
Ω
, 1000
Ω
or 3000
Ω
cells provided the excitation supply can excite one 350
Ω
bridge. Compute the current required to
excite the bridge by using the following formula:
Indicator Excitation Voltage / 350
Ω
= Bridge Current in amps
Example: if we have an indicator with a 5VDC excitation voltage, then (5 VDC) / (350
Ω
) = 0.0143 A.
The Simulator 4 will work with this system if the excitation supply can provide more than 0.014 A
(14 mA).
The power loading switch of the Simulator 4 also allows loading the power supply of an indicator with up to
8 - 350
Ω
cells or 16 - 700
Ω
cells.
What excitation voltages can I use? - The Simulator 4 was designed for use with excitation voltages of
5 VDC - 15 VDC. The maximum excitation voltage must not exceed 15 VDC!
Can I use Simulator 4 with AC excitations? - Bridge simulators like the Simulator 4 will work with
many low frequency AC excitation supplies of
±
7.5 VAC or lower. The switching frequency should be less
than 100 Hz for best results. Caution: Certain AC excitation instruments are very sensitive to inductive load-
ing. The Simulator 4 uses very stable wire-wound resistors which are designed to minimize induction. How-
ever, some induction is present and may cause problems with some meters.